This invention relates, in general, to processing within a computing environment, and in particular, to managing input/output (I/O) interruptions within such an environment.
Interruptions are used to alert processors that action is to be taken. There are different types of interruptions, including input/output (I/O) interruptions, which are initiated by I/O components of a computing environment. As an example, adapters external, but coupled to, a central processing complex initiate I/O interruptions for processors of a central processing complex.
In some computing environments, including one or more of those in which the central processing complex is based on the z/Architecture® offered by International Business Machines Corporation, an I/O interruption initiated by an external adapter is first seen as an Alert attention to a processor of the environment. The Alert attention is processed to determine whether an interruption initiative is to be set. If the initiative is to be set, then the processor sets it in an Interruption Queue Header under control of a lock. When the queue transitions from the empty state to the non-empty state, the processor initiates a broadcast of a command to all of the processors instructing them to set the initiative at the processors.
In another example, an external adapter directly initiates the setting of an interruption initiative, such as an I/O interruption initiative, at one or more of the processors. As one example, the adapter directly sends a request to a system controller (e.g., hardware) coupled to the adapter and the processors. The request designates a particular zone and I/O interruption subclass within the computing environment for which a pending interruption is to be set. The system controller then sends a command based on the request to the processors instructing them to set the initiative.
Subsequent to setting the interruption initiative, processors arbitrate to handle the interruption initiative, including resetting a pending interruption indicator.